Your WF-55 kit contains a turret board, already staked with turrets for you to add and solder your kit's
board-based components. Click here to open a page with
detailed photos of the layout of the components on this board.|
The top picture shows the components soldered in position. The bottom photo is
annotated with component numbers (C1, R4, etc). Use that as your guide to component layout.
Make sure to use the larger resistors - which are rated at 1W or 2W - in the appropriate position.
For example, there are three 100k resistors, one of which is substantially thicker than the other
two. The smaller pair are R3 and R5 in the preamp (below left), and the larger one is R13, connecting across
C7 in the high voltage part of the power supply (below right).
Five of the capacitors have a polarity that you need to follow:
* C3 negative towards bottom edge
* C4 negative towards bottom edge
* C5 negative towards bottom edge
* C6 negative towards bottom edge
* C7 negative towards bottom edge
In addition, the diodes (D1-D5) must also be inserted the correct way around. Follow the
example shown in the component layout diagram, paying close attention to the orientation of
the grey-silver bands at one end of each diode.
Most of the components are best mounted using the holes in the top of the turrets. However, it's best to
side mount the rectifier diodes, D1-D4 (as shown below). This makes it easier to connect the wires
from the power transformer when you get to the chassis wiring.
Ground and other connections
Once all of the components are in place on the turret board, use some of your kit's uninsulated
solid-core wire to make three short connections along the edge of the board - as shown in the
picture on the right.
First, solder two ground bus wires: the first to connect turrets A-D, and the
second to connect turrets E-I. These wires will connect all of these components to ground once the wiring is
complete. Finally, connect the three turrets J-L at the top of the board. Now you're ready to add the
wiring (see Part 6).
Note: There will be a pair of resistors left over - R1 and R2. This is normal;
put them to one side for the moment.
|Turret board soldering tips|
|* Do a 'dry run' before you start to solder. Line up all of the components in their correct
order, from left to right. This helps you to avoid mistakes and having to desolder components.|
* Even if you can read resistor colour codes easily, use your multimeter to check the resistance
value, just in case.
* Check twice and cut once - extending a component lead that you've mistakenly trimmed too short
is a pain, so double-check that you've got the correct component before cutting the lead.
* Aim for solder joints that are shiney and gently domed. Solder should 'flow' around the component
leads and turret surface - almost seamlessly.
* If a solder joint looks 'lumpy' or dull, you may have a poor joint, which can cause the amp not
to work (or even to work intermittently - a tricky problem to debug). If in doubt, resolder the joint.
* If the turret's top hole is crowded, with no room to fit another lead, don't worry - use the side of
the turret. There are side-ridges for this purpose - wrap the new lead around the turret's side
and solder it in position.